If the seawater carbonate ion concentration is 270_mol/kg, what is the approximate rate of calcification, and approximately how many days would i take 1 square meter of reef to accumulate 30mmol of calcium carbonate (CaCO3) ?

The calcification rate can be determined using the given graph. It is approximately 18 mmol CaCO₃ per m² per day. Thirty mmol of calcium carbonate divided by 18 mmol CaCO₃ per m² per day is equivalent to 1.67. Therefore, it will take 1.67 days to accumulate 30 mmol of calcium carbonate.